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Jun
29
comment Generating functions of bills
Perhaps you should emphasize that you want to find it by hand and not using a computer.
Jun
29
comment Generating functions of bills
Why do you have $1/(1-x)^2$?
Jun
26
answered The sum of squares of the first $n$ natural numbers.
Jun
25
comment $\sum_{n=1}^{\infty} a^{-n!}$ is transcendental ??
Just repeat the same proof and it will still work.
Jun
22
revised Difficult to comprehend markov chain and its characteristics
deleted 2 characters in body
Jun
22
comment Showing the following sequence is monotone decreasing
Try taking the derivative of $T\coth(\mu T)$ with respect to $T$.
Jun
22
answered Showing the following sequence is monotone decreasing
Jun
22
comment Difficult to comprehend markov chain and its characteristics
@Did I meant that sometimes there is more than one, if the chain is not ergodic.
Jun
22
awarded  proof-strategy
Jun
22
comment Meaning of finite, countably infinite, infinite?
Assuming the axiom of choice, an equivalent definition is that a set $S$ is infinite if there is a bijection between $S$ and a proper subset of $S$. So a set is finite if there is no bijection between it and any of its proper subsets.
Jun
21
revised How to combine the four Theorems in order to prove the statement?
added 3 characters in body
Jun
21
answered How to evaluate $\lim_{ n\to \infty }\frac{a_n}{2^{n-1}}$, if $a_0=0$ and $a_{n+1}=a_n+\sqrt{a_n^2+1}$?
Jun
21
comment Need help with checking whether a predicate logic formula is a tautology.
A tautology is a statement that is always valid. Is this statement always valid? If so, it is a tautology.
Jun
21
answered How to combine the four Theorems in order to prove the statement?
Jun
21
answered Need help with checking whether a predicate logic formula is a tautology.
Jun
21
answered Var$(X) = \mathbb{E}((X - \mathbb{E}(X))^2) = \mathbb{E}(X^2) - \mathbb{E}(X)^2$
Jun
21
answered Variance of number of tails minus heads
Jun
21
answered Do negative signs count as subtraction or multiplication?
Jun
21
answered Roll a die until, for the first time, the same side shows up two times in a row. Let $X$ be the number of rolls needed. compute $\mathbb{E}(X)$.
Jun
21
comment “off by 1” lottery probability
Voting to close, you're not stating the question in your post. We have to guess it and you're angry at us if we guess wrong.